A playground equipment of so-called log-walk horizontally placing a log of the thickness capable of walking, is installed in the parks. The playground equipment of the log-walk is popular with guardian as a playground equipment for nurturing balance sense. There is much demand for playground equipment maker because it can be configured easily. An example of the indoor playground equipment of the log-walk is disclosed in Japanese Unexamined Pat. App. Pub. No. 2000-262646.